Dyes have been widely used in a variety of technical fields. As an example in the field of photoelectric conversion devices such as solar cells, photosensitizing dyes are used in dye-sensitized photoelectric conversion devices. Such dye-sensitized photoelectric conversion devices are theoretically expected to have high efficiency and thought to be producible at a cost lower than that of traditional photoelectric conversion devices made with silicon semiconductors.
A dye-sensitized photoelectric conversion device has an electrode including an oxide semiconductor as a support on which a dye is supported. In such a dye-sensitized photoelectric conversion device, the dye is excited by absorbing incident light, and the excited dye injects electrons into the support to cause photoelectric conversion.
Techniques that have been studied to improve the conversion efficiency and durability of dye-sensitized photoelectric conversion devices include improvements in the dye-supporting ability of a support. Specifically, if physical or chemical adsorption ability of a dye to a support is increased, excited energy can be transferred with high efficiency from the dye to the support, and the dye can be prevented from leaching into the device (specifically, leaching into the electrolytic solution or the like). A technique of adding an anchor group such as a carboxylic acid group or a silanol group to dye molecules has been tried to improve the supporting ability (see Patent Literatures 1 to 3).
Solar cells are one of the important applications of dye-sensitized photoelectric conversion devices. Such solar cells are required to have high durability because of the nature of the intended use, but known dyes and photoelectric conversion devices made with such dyes still have insufficient performance.